The invention relates to a device for guiding and tensioning supply lines for working tools movable along a straight guide, e.g. supply lines of a hydraulic hammer drill on an advance mounting, wherein the advance of the working tool is implemented by means of a revolving transport chain driven by a sprocket wheel, and the supply line(s) are guided between the connections on the fixed guide and the connections on the working tool via a tension roller which causes a deflection by about 180° and is movable in advance direction downstream the working tool conjointly therewith in the same direction but at half the advance speed, wherein the tension roller is slidably guided transversely to its rotation axis on the guide for the working tool, and wherein the drive for the movement of the tension roller includes a pinion which engages the transport chain and interacts with a fixed chain on the opposite side.
According to a known design, the tension roller is guided via a tackle of the block-and-pulley type with loose rope pulley, wherein the loose pulley controls the movement of the tension roller. The drawback of such a design is the susceptibility of tackles to fail, in particular when subjected to rough handling in the area of such tools. Moreover, a tackle control can be actively controlled only in one direction whereas means for retraction and maintaining the tackle taut must be provided in the other direction.
The afore-described design is disclosed in U.S. Pat. No. 3,973,634, with the pinion, which engages the transport chain, engaging with its region that is opposite to the area of engagement in the transport chain in the fixed chain so that only few engaging teeth of the pinion are available to absorb the entire load.